Other References:

http://www.nhlbi.nih.gov/health/dci/Diseases/Sca/SCA_Causes.html

http://sickle.bwh.harvard.edu/scd_inheritance.html

http://www.google.com.co/search?hl=es&biw=1116&bih=470&defl=en&q=define:Sickle+cell+trait&sa=X&ei=ZKc1Tf_gHov3gAeV5JzOCw&ved=0CBkQkAE

http://themedicalbiochemistrypage.org/sicklecellanemia.html

http://www.sicklecelldisease.org/about_scd/faqs.phtml#people

http://www.nhlbi.nih.gov/health/dci/Diseases/Sca/SCA_Treatments.html

http://www.sicklecelldisease.org/about_scd/faqs.phtml#people

http://kidshealth.org/parent/medical/heart/sickle_cell_anemia.html#

http://www.everythingsicklecell.com/coping_skills.html

http://www.answerbag.com/q_view/1964188